Trifluoromethylmercaptoacetamidocephalosporins

ABSTRACT

THIS INVENTION IS DIRECT TO ANITBACTERIAL COMPOUNDS, IN PARTICULAR, TO 7 - TRIFLUOROMETHYLMERCAPTOACETAMIDOCEPHALOSPORINS.

United States Patent M 3,828,037 TRIFLUOROMETHYLMERCAPTOACETAMIDO- CEPHALOSPORINS Robert M. De Marinis, King of Prussia, and John R. E.

Hoover, Glenside, Pa., assignors to Smithkline Corporation, Philadelphia, Pa. No Drawing. Filed July 20, 1972, Ser. No. 273,571 Int. Cl. C07d 99/24 U.S. Cl. 260-243 C 7 Claims ABSTRACT OF THE DISCLOSURE This invention is directed to antibacterial compounds, in particular, to 7 trifluoromethylmercaptoacetamidocephalosporins.

This invention relates to cephalosporins with a new 7- acyl group, in particular to the 7-trifluoromethylmercaptoacetamidocephalosporins. The compounds have antibacterial activity.

Cephalosporins with a variety of acyl groups at the 7- position have been disclosed and claimed in the prior art. For example, 7-alkylmercaptoacetamidocephalosporanic acids have been disclosed in U.S. Pat. No. 3,297,298 and others. Also, 7-methylmercaptoacetamido 3 [N- n-butyl-N (2 diethylaminoethyl)aminothiocarbonylthiomethyl] 3 cephem 4 carboxylic acid and other similar compounds have been disclosed and/or claimed in U.S. Pats. Nos. 3,329,515, 3,329,516 and 3,573,298. However, no cephalosporins with a trifluoromethylmercapto group in the 7-acyl substituent have been described.

The novel compounds of this invention have the following structure:

in which:

A is hydrogen, acetoxy, pyridinium, methoxy, methylthio or S-Het;

Het is a 5 or 6 membered heterocyclic ring containing 1-4 hetero atoms selected from the group consisting of N, O and S and being unsubstituted or substituted with one or two groups selected from the group consisting of alkyl, alkoxy, alkylthio, each alkyl residue being one to four carbon atoms; C -C cycloalkyl, halogen, hydroxy, mercapto, trifluoromethyl and NR and R is hydrogen or C -C alkyl.

A preferred group of compounds is that where A is S-Het. Particularly preferred are those compounds where Het is a substituted or unsubstituted tetrazole, thiadiazole, oxadiazole or triazole.

Included within the scope of this invention are the pharmaceutically acceptable salts that are formed by reaction of the cephalosporin acid with a pharmaceutically acceptable base. It is recognized that when the substituent on the heterocyclic group is hydroxy or mercapto that it is possible for the substituent to exist in more than one tautomeric form, i.e. the hydroxy or 0x0 and the mercapto or thiono forms. The compounds may exist exclusively as one tautomer or may be in equilibrium between the other forms; however, these are all included within the scope of this invention.

The compounds are prepared by acylation of the appropriate 7-aminocephalosporin, for example, 7-aminocephalosporanic acid (7 ACA), 7 aminodesacetoxycephalosporanic acid (7-ADCA) or 7-amin0 3 heterocyclicthiomethyl 3 cephem 4 carboxylic acid, with 3,828,037 Patented Aug. 6, 1974 trifluoromethylmercaptoacetic acid. The carboxyl group of the acetic acid is activated by one of the common methods known to one skilled in the art such as mixed anhydride, acid halide or activated ester. In addition, acylation of esters of the cephalosporin nucleus may be done by using a coupling reagent such as dicyclohexylcarbodiimide (DCC) or N,N'-carbonyldiimidazole.

Trifiuoromethylmercaptoacetic acid is prepared by treating iodoacetic acid with silver trifluoromethylmercaptan. The acetic acid is converted to an activated ester by condensing N-hydroxysuccinimide and the acid, with DCC being used as the condensing reagent. This activated ester is then used to acylate the appropriate 7 aminocephalosporin. Alternatively, trifluoromethylmercaptoacetyl chloride, prepared from trifluoromethylsulfenyl chloride and ketene [J. Org. Chem., 37:1340 (1972)], may be used as the acylating reagent.

The compounds of this invention have antibacterial activity against both Gram-positive and Gram-negative organisms. Minimum inhibitory concentrations (MIC) ranged from 0.1 to 200 ig/ml. in an in vitro screen against a broad variety of bacteria; however, most of the MICs were less than 50 ,ug/ml. The MICs for 7-trifiuoromethylmercaptoacetamidocephalosporanic acid (I), 7 trifluoromethylmercaptoacetamido 3 (1 methyltetrazol 5 ylthiomethyl) 3 cephem-4-carboxylic acid (H), and 7-trifluoromethylmercaptoacetamido 3- (S-methyl 1,3,4 thiadiazol-2-ylthiomethyl)-3-cephem- 4 carboxylic acid (III) against representative bacteria are shown in Table I. In addition, the compounds exhibit antibacterial activity in an in viva screen when administered subcutaneously.

TABLE I MIC g/ml.)

Bacteria I II III S. aureus, HE 127.. 0. 4 0. 4 0. 4 Strep 171109., 0 203.-.. 0. 1 0. 1 0. 1 Strep faecalis, HE 343 25 25 12.5 E. coli., EH 3377 6. 3 l. 6 3. 1 K. pneumm, SK 4200.----- 0.8 0.8 1. 6 Preudomtmas sp., HH 63.... 200 200 200 Entero. acrogenes 50 1. 6 6. 3

These compounds are formulated and administered in the same manner as other cephalosporin compounds. The dose and mode of administration are within the skill of the art.

The following examples illustrate the invention but are not to be understood as limiting the scope thereof.

EXAMPLE 1 N-hydroxysuccinimidyl trifluoromethylmercaptoacetate Trifluoromethylmercaptoacetic acid was prepared by allowing equal molar quantities of trifiuoromethyl mercaptan silver salt and iodoacetic acid to stand at room temperature in acetone for 11 days. The solid was collected and washed with acetone. The combined filtrates and washings were decolorized with charcoal and evaporated to an oil which was distilled; b.p. l00/23 mm.

A solution of the above acetic acid (4.8 g., 0.03 mol.) and N-hydroxysuccinimide (3.45 g., 0.03 mol.) in tetrahydrofuran (50 ml.) was stirred and cooled to 0 before 13y similar methods the trifluoromethylmercaptoacetic acld can be reacted with other hydroxy compounds to give other activated esters such as 2,4-dinitrophenyl.

EXAMPLE 2 7-trifluoromethy]mercaptoacetamido-3-methylcephalosporanic acid 7-aminocephalosporanic acid (544 mg., 2 mmol.) was suspended in dry DMF (10 ml.) and triethylamine was added until solution was efiected. The activated ester from Example 1 (514 mg, 2 mmol.) was added and the reaction was stirred for 2.5 hours at room temperature. The mixture was poured into water (50 ml.) and the aqueous solution was acidified and then extracted with ethyl acetate. The dried extracts were evaporated to an oil which crystallized. The solid product was collected, triturated with ether, and dried, m.p. 139 (dec.).

EXAMPLE 3 7-trifluoromethylmercaptoacetamido-3-methylcephem-4-carboxylic acid 7 aminodesacetoxycephalosporanic acid (1.07 g., 5 mmol.) was suspended in dry DMF (25 ml.) and 1,5- diazobicyclo[4.3.0]non-5-ene was added until a slight cloudiness just remained. The activated ester from Example 1 (1.28 g., 5 mmol.) was added and the mixture was stirred for two hours at room temperature. The reaction was poured into water (200 ml.), acidified, and extracted with ethyl acetate. The extracts were washed with water, dried and evaporated to a product which crystallized on standing. The product was recrystallized from chloroform; m.p. 108 (dec.).

EXAMPLE 4 7-trifluoromethylmercaptoacetamido 3 (5-methyl-1,3,4- thiadiazol-2-ylthiomethyl)-3-cephem-4-carboxylic acid To a suspension of 7-amino-3-(5-methyl-l,3,4-thiadiazl-2-ylthiomethyl)-3-cephem-4-carboxylic acid (628 mg., 2 mmol.) in dry DMF (20 ml.) was added triethylamine until only a slight cloudiness remained. The activated ester of Example 1 (514 mg., 2 mmol.) was added in one portion and the reaction mixture was stirred for three hours at room temperature. The reaction was poured into ice water (100 ml.) and the aqueous solution was acidified to pH 1.5 with 3N HCl and extracted with ethyl acetate. The combined extracts were washed with water and then saturated saline solution. The dried organic phase, containing the title compound, was concentrated to ca. 20 ml. The dropwise addition of a 30% solution of sodium Z-ethylhexanoate in isopropanol precipitated the sodium salt which was collected and dried.

EXAMPLE 7-trifluoromethylmerc aptoacetamido 3 1-methyl-tetr azol-S-ylthiomethyl) -3-cephem4-carboxylic acid 7 amino-3-(l-methyl-tetrazol-S-ylthiomethyl)-3-cephem-4-carboxylic acid (984 mg., 3 mmol.) and the activated ester from Example 1 (771 mg, 3 mmol.) were reacted by the same procedure as in Example 4. Evaporation of the washed and dried extracts gave the title compound. The product was dissolved in ethyl acetate, heated with charcoal for minutes, filtered, and treated with a 30% solution of sodium 2-ethyl-hexanoate in isopropanol. The sodium salt was precipitated by the addition of ether, collected and dried. The dried powder was dissolved in acetonitrile at room temperature and allowed to stand. It deposited white crystals of the sodium salt of the title compound.

EXAMPLE 6- 7-trifiuoromethylmercaptoacetamido-3-(5-n1ethyl-1,2,4- triazol-3-ylthiomethyl)-3-cephern-4-carboxylic acid 7-amino-3-(5-methyl 1,2,4 triazol-3-ylthiomethyU-3- cephem-4-carboxylic acid (1.14 g., 3.5 mmol.) and the activated ester of Example 1 (0.89 g., 3.5 mmol.) were reacted according to the procedure of Example 4. Evaporation of the ethyl acetate extracts gave a gummy residue which crystallized on standing. The product was recrystallized from acetonitrile to give the pure title compound.

EXAMPLE 7 7-trifluoromethylmercaptoacetamido-3-(5-hydroxy-1,2,4- triazol-3-ylthiomethyl)-3-cephem-4-carboxylic acid To a cold solution (20) of 7-amino-3-(5-hydroxy- 1,2,4 triazol-3-ylthiomethy1)-3-cephem-4-carboxylic acid (3.39 g., 0.01 mole) in a mixture of acetone (62.5 ml.) and 3% NaHCO (62.5 ml.) is added dropwise over a 30 minute period a solution of trifiuoromethylmercaptoacetyl chloride (2.24 g., 0.012 mol.) in acetone (20 ml.). The solution is maintained at pH 8 by adding 10% sodium hydroxide as needed. The reaction is stirred for 20 minutes at 15 to -20 and then allowed to warm to room temperature. The solution is washed with ether, covered with ethyl acetate and acidified to pH 2. The aqueous phase is separated and extracted with ethyl acetate. The combined ethyl acetate phases are combined, washed with water, dried, and evaporated to give the title compound.

EXAMPLE 8 When an equivalent amount of a 7-amino-3-heterocyclicthiomethyl-3-cephem-4-carboxylic acid listed below is substituted in the procedure of Example 4 for 7-amin0-3- (5-methyl-l,3,4-thiadiazol 2 ylthiomethyl)-3-cephem-4- carboxylic acid, the appropriate 7-trifluoromethylmercaptoacetamido-S-heterocyclicthiomethyl 3 cephem-4-carboxylic acid is obtained.

7-amino-3-( 1,3 ,4-thiadiazol-Z-ylthiomethyl) -3-cephem- 4-carboxylic acid 7-amino-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3 (5 -ethyl-1,3 ,4-thiadiazol-Z-ylthiomethyl) -3- cephem-4-carboxylic acid 7 -amino-3 5-n-butyl-1,3,4-thiadiazol-Z-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3-(S-dimethylamino-1,3,4-thiadiazo1-2-ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-(5-rnercapto-1,3,4-thiadiazol-2-ylthomethyl)- 3-cephem-4 carboxylic acid 7-amino-3- 3-methy1thio- 1,2,4-thiadiazol-S-ylthiomethyl 3-cephem-4-carboxylic acid 7- amino-3- (3 -methyl- 1,2,4-thiadiazol- 5 -ylthiomethyl) -3- cephem-4-carboxylic acid 7-amino-3-(tetrazol-S-ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-( 1,2,4-triazol-3-ylthiomethy1) -3-cephem-4- carboxylic acid 7-amino-3-(4-methyl-1,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxy1ic acid 7-amino- 3- 4, 5- dimethyl- 1 ,2,4-triazol-3-ylthiomethy1) 3-cephem-4-carboxylic acid 7-amino-3-( 1 ,S-dimethyl-1,2,4-triazol-S-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3-(4-methyl-5-trifluoromethyl-1,2,4-triazol-3- ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-(5-ethy11,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3-(4-ethyl-1,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3- l-methyl- 1 ,2,4-triazol- 5-ylthiomethy1) -3- cephem-4-carboxylic acid 7-amino-3 l-methyl-1,2,4-triazol-3-ylthiomethyl) -3- cephem-4-carboxylic acid 7-amino-3-(1-ethy1-1,2,4-triazol-5-ylthiomethyl)-3- cephem-4-carboxylic acid '7-amino-3- l-ethyl-1,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3- (4-allyl-1,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxy1ic acid 7-amino-3-(S-methoxymethyl-1,2,4-triazol-3-ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-(S-cyclopropyl-1,2,4-triazol-3-ylthiomethyl)- 3-cephem-4-carboxylic acid 7-amino-3-(S-bromo-1,2,4-triazol-3-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3-(5-hydroxy-4-methyl-1,2,4-triazol-3-ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-(5-hydroxy-4-ethyl-1,2,4-triazol-3-ylthiomethyl) -3-cephem-4-carboxylic acid 7-amino-3- 1,2,3-triazol-4-ylthiomethyl)-3-cephem-4- carboxylic acid 7-amino-3- l-methyl-1,2,3-triazol-5-ylthiomethyl) -3- cephem-4-carboxylic acid 7 -amino-3-( l,3,4-oxadiazol-Z-ylthiomethyl) -3-cephem-4- carboxylic acid 7-amino-3- (S-methyl- 1 ,3,4-oxadiazol-Z-ylthiomethyl) -3- cephem-4-carboxylic acid 7-amino-3-(4-pyrimidylthiomethyl)-3-cephem-4- carboxylic acid '7-amino-3-(Z-pyrazinylthiomethyl)-3-cephem-4- carboxylic acid 7-amino-3-(3-pyridylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3- (4-pyridylthiomethyl) -3-cephem-4-carboxylic acid.

EXAMPLE 9 When an equivalent amount of 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid is substituted into the procedure of Example 4, 7-trifiuoromethylmercaptoacetamido-3-methoxymethy1-3-cephem-4-carboxylic acid is obtained.

Acylation of 7-amino-3-methylthiomethyl-3-cephem-4- carboxylic acid according to the procedure of Example 4 gives 7 trifluoromethylmercaptoacetamido-3methylthiomethyl-3-cephem-4-carboxylic acid.

EXAMPLE 10 7-trifluoromethylmercaptoacetamido-3- l-pyridiniummethyl) -3-cephem-4-carboxylic acid To a solution of 7-trifluoromethylmercaptoacetamidocephalosporanic acid sodium salt (4.36 g., 0.01 mol.) in water (25 ml.) is added potassium thiocyanate (2.23 g., 0.023 mol.) and pyridine (2.2 ml., 0.028 mol.). The reaction is heated at 65-70 for seven hours and then is cooled. The mixture is diluted with water (100 ml.) and the aqueous solution is chromatographed on a column of cross-linked polystyrene polymer (Amberlite XAD-Z). The inorganic salts are eluted with water and then the product is eluted with 95% ethanol. Evaporation of the eluant gives the product.

EXAMPLE 11 An injectable pharmaceutical composition is prepared by dissolving 500 mg. of sodium 7-trifiuoromethylmercaptoacetamido-3-(1 methyltetrazol-S-ylthiomethyl)-3-cephem-4-carboxylate in sterile water or sterile normal saline Mg. Cephalosporin 500 Lactose 250 Magnesium stearate We claim: 1. A compound of the formula:

O= N CHaA COOH in which:

A is S-Het;

Het is a S or 6 membered heterocyclic ring containing 1-4 hetero atoms selected from the group consisting of N, O and S and being unsubstituted or substituted with one or two groups selected from the group consisting of alkyl, alkoxy, alkylthio, each alkyl residue being one to four carbon atoms; C -C 'cyclo alkyl, halogen, hydroxy, mercapto trifluoromethyl and NR and R is hydrogen or C -C alkyl,

or a pharmaceutically acceptable salt thereof.

2. A compound as claimed in claim 1 Where Het is tetrazolyl, thiadiazolyl, triazolyl or oxadiazolyl, unsubstituted or substituted with one or two C -C alkyl groups, a hydroxy, or a mercapto group.

3. A compound as claimed in claim 2 being the compound 7-trifiuoromethylmercaptoacetamido-3-(S-methyl- 1,3,4-thiadiazol 2 ylthiomethyl)-3-cephem-4-carboxylic acid.

4. A compound as claimed in claim 2 being the compound 7-trifiuoromethylmercaptoacetamido-3-(l-methyltetrazol-S-ylthiomethyl)-3-cephem-4-carboxylic acid.

5. A compound as claimed in claim 2 being the compound 7 trifluoromethylmercaptoacetamido-3-(1,2,3-triazol-4-ylthiomethyl)-3-cephem-4-carboxylic acid.

6. A compound as claimed in claim 2 being the compound 7-trifluoromethylmercaptoacetamido-3-(S-methyl- 1,2,4-triazol-3-ylthiomethyl)-3-cephem-4-carboxylic acid.

7. A compound as claimed in claim 2 being the compound 7-trifiuoromethylmercaptoacetamido-3-(S-hydroxy- 1,2,4-triazol-3-ylthiomethyl)-3-cephem-4-carboxylic acid.

References Cited UNITED STATES PATENTS 3,647,788 3/1972 Clark et a1 260-243 C NICHOLAS S. RIZZO, Primary Examiner US. 01. X.R. 424246 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION Q PATENT NO. 3,828,037

DATED August 6, 1974' TNVENTQMS) Robert M. DeMarinis and John R. E. Hoover It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 24, change "3,297,298" ,to --3,297,692-- Column 1, line 29, change "3,329,515, 3,329,516" to Column 3, line 5, delete "B-methyl" Column 3, line 21., change "cephem" to -3-cephem Column 4, line 44, change "2-ylthomethyl" to 2-ylthiomethyl--- Signed and Sealed this fourth Day of November 1975 {SEAL} Arrest:

RUTH C. MASON C. MARSHALL DANN 8 /7 Commissioner oflamm and Trademarks 

